Defining Faecal Calprotectin Thresholds as a Surrogate for Endoscopic and Histological Disease Activity in Ulcerative Colitis—a Prospective Analysis

• Published in: Journal of Crohn's and colitis 2019-03, Vol.13 (4), p.424-430
• Main Authors: Walsh, Alissa, Kormilitzin, Andrey, Hinds, Christopher, Sexton, Vanashree, Brain, Oliver, Keshav, Satish, Uhlig, Holm, Geddes, John, Goodwin, Guy, Peters, Michele, Collins, Gary, Travis, Simon
• Format: Article
• Language: English
• Subjects: Area Under Curve; Biomarkers - analysis; Biopsy; Colitis, Ulcerative - diagnostic imaging; Colitis, Ulcerative - pathology; Colon - pathology; Colonoscopy; Feces - chemistry; Humans; Intestinal Mucosa - pathology; Leukocyte L1 Antigen Complex - analysis; Prospective Studies; ROC Curve; Severity of Illness Index; Symptom Assessment
• ISSN: 1873-9946; 1876-4479
• DOI: 10.1093/ecco-jcc/jjy184

Abstract Background Faecal calprotectin [FCal] levels are used as a surrogate marker for mucosal inflammation, but thresholds for defining endoscopic or histological disease activity in ulcerative colitis [UC] remain unclear. Methods Using validated indices, prospective measurements of FCal, symptoms [Simple Colitis Clinical Activity Index, SCCAI], endoscopic [Ulcerative Colitis Endoscopic Index of Severity, UCEIS] and histological activity [Nancy index] were made over 6 months in patients enrolled into the TrueColours UC web-based monitoring programme. Repeated measurements correlation was performed between FCal and SCCAI, UCEIS, and Nancy indices using definitions for remission and active disease [UCEIS: remission ≤1, active ≥4; Nancy: remission ≤1, active ≥2; combined criteria: remission UCEIS ≤1 and Nancy ≤1, active UCEIS ≥4 and Nancy ≥2]. Receiver operating characteristic curves investigated FCal thresholds after maximising sensitivity for active disease. Results In 39 patients followed prospectively for 6 months, correlation coefficients between FCal and SCCAI, UCEIS, and Nancy indices were 0.271 (95% confidence interval [CI] 0.114–0.415), 0.741 [95% CI 0.289–0.922], and 0.876 [95% CI 0.605–0.965], respectively. Median FCal thresholds for remission using endoscopic, histological, or combined criteria were 71 μg/g [range 8–624], 91 μg/g [range 8–858], and 67 μg/g [range 8–479], respectively. The FCal threshold above which active disease was confirmed was 187 μg/g for UCEIS (area under the curve [AUC] 0.915), 72 μg/g for Nancy [AUC 0.824], and 187 μg/g for combined endoscopic and histological criteria [AUC 0.936]. Conclusions Correlation between FCal and symptoms in UC is weak. In contrast, the correlation between FCal and endoscopic or histological activity is strong. An FCal ≥72 μg/g indicates histological inflammation [Nancy ≥2] and ≥187 μg/g indicates endoscopically active disease [UCEIS ≥4], whether combined with histopathology or not.